Effect of Neurofeedback on Perceptual Organization, Visual and Auditory Memory in Children with Attention Deficit/Hyperactivity Disorder.

Objectives
Neurofeedback is a noninvasive treatment that changes brain activity in children with attention-deficit/hyperactivity disorder and thereby improves performance in these children. We examined the effect of neurofeedback on perceptual organization, visual and auditory memory in children with attention-deficit/hyperactivity disorder.


Materials & Methods
This study was quasi-experimental with pre-test, post-test design, and control group. The sample included 20 children with attention-deficit/hyperactivity disorder were selected through convenience sampling in Khorramabad, central Iran in 2017. The sample was divided into control and experimental groups. Pre-test included Rey-Osterrieth complex figure and Wechsler digit span. Rey-Osterrieth complex figure test was used to measure perceptual organization and visual memory. Wechsler digit span was used to measure auditory memory. After conducting pre-test, the experimental group participated in neurofeedback training sessions. Theta/Beta protocol was applied for all participants. The control group did not receive any intervention. Then post-test was conducted on two groups.


Results
Neurofeedback training significantly improved visual memory (P<0.001) but neurofeedback training had no significant effect on the perceptual organization (P>0.05). Moreover, neurofeedback training enhanced auditory short-term memory and auditory working memory (P<0.05).


Conclusion
Neurofeedback improved neurocognitive abilities in children with attention-deficit/hyperactivity disorder.


Introduction
Attention deficit hyperactivity disorder is a neurodevelopmental disorder described by inattention, impulsivity, and hyperactivity.
Attention deficit hyperactivity disorder frequently occur in childhood and have prevalence rate proximally 2% to 9% (1), valued to affect up to 7% of children and 5% of adult universal (2). The disorder is determined by three subtypes: predominantly inattentive type, primarily hyperactive-impulsive type and combined type (3). This condition is related to numerous negative consequences such as academic problems, behavioral disorder, social and familial disturbance (4). These children need to have academic support, retention grade and dropping out occurs among those at high levels and more are placed in special settings (2).
Authors consider damaged neurocognitive functioning as a central dysfunction of the ADHD reflected in lacks, a range of neurocognitive dysfunction such as attention, inhabitation and working memory (5). Several theories attempted to explain symptoms of attention deficit hyperactivity disorder. Functional working memory model proposes that working memory is a central deficit that underlines the attention deficit hyperactivity disorder symptoms. Hyperactivity (as a symptom of ADHD) is a compensatory function for increased cortical arousal demand for influential working memory. In these people neural areas such as frontal lobe do not work well, therefore dopamine and norepinephrine in these areas increase the motor activity (4).
Working memory deficit is related to ADHD as well as academic problems. The deficit in working memory adversely influenced processes such as focusing attention, inhabitation of unrelated stimuli, recognizetion the meaning of the stimulus and selecting goals. These cognitive abilities are necessary for learning (2). Working memory was assessed in children with and without ADHD.
Significantly younger children with ADHD had working memory deficit (2).
In this disorder, stimulant medication usually is recommended and assumed that it is an influential treatment of decreasing behavioral symptoms and improving neurocognitive dysfunction in children with ADHD. Nevertheless, the stimulant medication has different side effects including sleep problems, loss of appetite, and headache.
Additionally, there is inadequate data about the long-term effect of this treatment (5).
Neurofeedback is noninvasive, without medicine method of brain training that can help the diversity of disorders such as pain, fatigue, depression, anxiety, sleep disorders, cognitive decline, autism, attention and hyperactivity disorder, and posttraumatic stress disorder (6,7). This method improves cognitive performance as well as regulate stress level, emotional and behavioral functioning (6). Therapists developed neurofeedback as an alternative treatment for children because they assumed that ADHD is a neurologically disorder decreasing ability of attention and behavioral control. This treatment began around 30 yr ago (8). Neurofeedback is a technique that can permit the brain to acquire self-regulation skills.
These abilities change brain activity and lead to symptomatic and behavioral modifications.
Throughout neurofeedback, brain performance is supervised by electrodes located on the vertex and feedback to the person by auditory and visual stimulus produced through the computer without presenting any disturbing stimulus into the brain (7). Two training protocols (theta/beta training and slow cortical potentials) are typically used in Iran J Child Neurol. Summer 2019 Vol. 13 No. 3 children with ADHD (8). Children with ADHD indicate increased theta (4-8Hz) and decreased beta (13-20 Hz) activity in EEG of brain activity.
Increased theta and decreased beta play role in decline of attention and concentration in children with ADHD. Thus a protocol that frequently used in ADHD children, cons its os decreasing theta and increasing beta activity (5).
Since the first study that used neurofeedback treatment in ADHD in 1979, a large number studies have examined the special effects of this treatment on diverse symptoms of ADHD for example inattention, impulsivity, and hyperactivity  The aim of Theta/Beta protocol is to inhibit theta (4-8 Hz) and reinforce beta (13-20 Hz) activity.
The signal employed in neurofeedback was very much similar to a computer game so that points are gained during three different games: a worm going toward the finish line, a monkey climbing a tree, and a face smiling. There was 30 sec break between each of these three games.
In the first 3 min of the first session, the baseline was ascertained by the trial of games using measure the Theta/Beta ratio. The participants were asked to concentrate on games. They must have reduced theta amplitude (4-8 Hz) below the baseline while increasing the beta amplitude (16-20 Hz) above the baseline.

Rey-Osterrieth complex figure test
Rey-Osterrieth complex figure test designed through Andre Rey in 1941 and expanded through Paul-Alex Osterrieth in 1944 (11). This test is used to assess visuospatial abilities, attention, executive function (11), perceptual organization  Rey-Osterrieth complex figure test is usable in the survey of normal and atypical development in children (12). It is usually used in dementia, mild cognitive impairment, diabetes type 2, attention deficit and hyperactivity disorder and multiple sclerosis (11).

Digit Span subtest from Wechsler intelligence scale for children
Wechsler digit span is an old neuropsychological test used for the measure of auditory working memory (14). This subtest is composed of twopart, digits forward and digit backward. In part one, subjects asked to listen to a digit span, then repeat it sequentially (forward). The digit spans include 3 to 9 digits and each digit span has two trails (15,16).
In part two, subjects required to listen to digits and repeat them backward. The digit spans composed of 2 to 8 digits that expressed one second each digit. Thus in each subject digit span measured for two-part (forward, backward). Factor analysis has determined that digit span forward is a task for evaluation of short-term memory and backward digit span is a task for assessment of working memory (14)(15)(16).

Results
According to Table 1, there was no significant difference between the average scores of perceptual organization (F= .08 & P=.78) between the experimental and the control groups. There was a significant difference between the average scores of visual memory (F= 21.97 & P=0.001) between the experimental and the control groups (Table 2).

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There was a significant difference between the average scores of working memory (F= 30.09 & P=0.001) between the experimental and the control groups (Table 3). Thus children could learn to be attentive because basic neural networks changed and strengthen (3). In a review symptoms in some persons were expressed with ADHD created by sleep problems (19). Neurofeedback through improvement of sleep spindle and decrease sleep problems can progress outcomes in the individual with ADHD (19). In addition, neurofeedback was a self-regulation training that enhanced control on the brain and decreases abnormal brain activity, subsequently improve brain functions such as memory (20).
The sample size was a potential limitation in this study and results hardly related to the population of In conclusion, neurofeedback training did not make a significant difference in the perceptual organization in pre-test and post-test. One explanation for this result is that scores of the subject in pre-test of the perceptual organization was high rather than other assessments, therefore less improvement in the perceptual organization could be expected.